1. Field of the Invention
This invention relates to a sample analyzer for analyzing a blood sample, a urine sample and the like and its components used therein and, particularly, to a versatile and portable sample analyzer.
2. Description of Related Art
Art hitherto known in relation to this invention is as follows.
A small-scale automatic analyzer comprising a reaction vessel disk having a reaction table with its circumferential portion equidistantly divided into a plurality of portions, a plurality of reaction vessels held by the reaction vessel disk, means for transporting the respective reaction vessels to a sample dispenser, to an agent dispensing position and to an optically measuring position, means for sucking and dispensing a required amount of a sample into the reaction vessel, and means for optically analyzing the sample in the reaction vessel (see, for example, Japanese Unexamined Patent Publication No. 11-94842 (1999));
A pipette comprising a hollow pipe having an end sealed with a seal member, and a suction port provided in a side wall of the pipe adjacent in the vicinity of the end (see, for example, U.S. Pat. No. 5,969,272); and
A pipette comprising a thin suction pipe for sucking a liquid sample, and a thin vent pipe for ventilation during the suction, the suction pipe and the vent pipe being disposed in parallel (see, for example, U.S. Pat. No. 5,969,272).
There have been proposed various types of blood analyzers for analyzing samples, for example, blood. Most of the recent blood analyzers have a greater size and a higher operation speed to handle a multiplicity of samples in a short time. In addition, the operation of the blood analyzers is complicated, so that special operators should be employed as regular staff. Local hospitals and private clinics which do not frequently need blood analyses currently commission a special blood analysis center to perform the blood analyses. However, it is impossible to immediately obtain the results of blood analyses in an emergency case. Therefore, there is a demand for a highly accurate, easy-to-operate and small-scale automatic blood analyzer.
Such a demand is applied to not only the blood analyzer but also a urine analyzer and the like.
In such a sample analyzer, it is preferred to employ a so-called AD system (Autodilution system) in which the liquid sample is sucked and quantified by a suction device such as a syringe pump having a pipette so that the analyzer may have a smaller scale with its more simplified construction. However, in the case of this system, when the pipette is inserted in a vacuum blood sampling tube (a rubber-capped tube) employed as a sample container, a negative pressure is liable to remain in the vacuum blood sampling tube. Accordingly, the sucking operation of the suction device is not smoothly performed, resulting in erroneous quantification. Thus, there is a problem that the analysis of the sample cannot be performed accurately.
On the other hand, if a conventional vent pipe is attached to the pipette in parallel, the analyzer needs to further provide a cleaning flow system for cleaning the vent pipe, so that the construction of the analyzer is complicated.